The present invention relates to a print head of the type in which individual print needles or styli are propelled forward, individually and in accordance with a program, to be retracted after they have impacted upon a printing surface. The forward or advance motion is usually caused by an electromagnet, the retraction results from spring bias. There are as many electromagnets as there are needles.
U.S. Pat. No. 3,929,214 is representative of this state of the art. The electromagnets are arranged in a circle, and each one operates an armature. The armatures are positioned by means of a star-shaped connecting element having radial outward extending holding arms for engaging the armatures. The particular device disclosed in this patent requires a certain degree of lateral play between armature and spring arm to assure that the armature is freely pivotable. This play, however, can translate into a fairly large, lateral pivot motion because the armature is much longer than it is wide. This lateral pivot motion must be impeded and requires, therefor, certain guidance. It must be observed, however, that particularly in rapid action devices guide elements and structure experience more or less rapid wear.